Some bottles for cosmetic products are provided with a pump configured to aspirate the cosmetic product contained in the reservoir of the bottle in order to dispense it, for example by means of a nozzle or through a simple opening. The product can thus be extracted or atomised from the bottle in order to allow application thereof. The pump is often actuated by means of a push button on which the user exerts pressure in order to trigger the functioning of the pump. A pump comprises in particular a pumping chamber, the volume of which varies to allow aspiration of the product in the chamber through an inlet orifice, when the volume increases, and then expulsion thereof out of the chamber through an outlet orifice, when the volume in the chamber decreases. The product emerges from the chamber in a dispensing pipe, which leads it to the opening or nozzle normally arranged on the push button.
Various kinds of pump are known, each having particular characteristics, in order to function specifically either with low-viscosity liquid products or with viscous liquid products such as creams or foams. Thus there exist pumps, the chamber of which is formed by a rigid body and a piston that closes off the chamber, and the movement of which in the body reduces or increases the volume of the chamber. The movement of the piston is in general controlled by actuating the push button. Such a pump is used in particular for liquid products to be vaporised.
There exist other pumps generally intended for more viscous products, the chamber of which is defined to a great extent by a flexible membrane, also referred as a “bellows”. The volume of the chamber is controlled by deformation of the membrane. In the non-deformed configuration of the membrane, the volume of the chamber is maximum. When the membrane is deformed, the volume of the chamber decreases, preferably to a volume low enough for a maximum amount of product to emerge from the chamber. Such pumps also have the advantage of avoiding having to use a metal spring, the components of the pump being made from plastics material.
The document FR 2804728 is for example known, which describes a deformable-membrane pump provided with slots as inlet and outlet orifices for the pumping chamber. In this pump, the membrane has a particular form and is held in a compartment to control the way in which it folds and unfolds. This is because it is wished to prevent the membrane deforming in an undesired configuration, which would risk damaging it and impairing the correct functioning of the pump.
Another document FR 2915467 shows a pump with a membrane having a bellows form in the form of an accordion. The bellows folds and unfolds along folding lines of the bellows. However, the membrane is divided into a plurality of parts attached firstly to the push button and secondly in the body of the pump. Such a pump is consequently difficult to assemble and therefore complex and expensive to manufacture.